EP1192342A1 - Method for controlling a combustion engine, and arrangement for such a method - Google Patents
Method for controlling a combustion engine, and arrangement for such a methodInfo
- Publication number
- EP1192342A1 EP1192342A1 EP00944512A EP00944512A EP1192342A1 EP 1192342 A1 EP1192342 A1 EP 1192342A1 EP 00944512 A EP00944512 A EP 00944512A EP 00944512 A EP00944512 A EP 00944512A EP 1192342 A1 EP1192342 A1 EP 1192342A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- engine
- switch
- air
- mode
- fuel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/30—Controlling fuel injection
- F02D41/3011—Controlling fuel injection according to or using specific or several modes of combustion
- F02D41/3064—Controlling fuel injection according to or using specific or several modes of combustion with special control during transition between modes
- F02D41/307—Controlling fuel injection according to or using specific or several modes of combustion with special control during transition between modes to avoid torque shocks
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B75/00—Other engines
- F02B75/12—Other methods of operation
- F02B2075/125—Direct injection in the combustion chamber for spark ignition engines, i.e. not in pre-combustion chamber
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D2250/00—Engine control related to specific problems or objectives
- F02D2250/18—Control of the engine output torque
- F02D2250/21—Control of the engine output torque during a transition between engine operation modes or states
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/021—Introducing corrections for particular conditions exterior to the engine
- F02D41/0235—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus
- F02D41/027—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus
- F02D41/0275—Introducing corrections for particular conditions exterior to the engine in relation with the state of the exhaust gas treating apparatus to purge or regenerate the exhaust gas treating apparatus the exhaust gas treating apparatus being a NOx trap or adsorbent
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/30—Controlling fuel injection
- F02D41/3011—Controlling fuel injection according to or using specific or several modes of combustion
- F02D41/3017—Controlling fuel injection according to or using specific or several modes of combustion characterised by the mode(s) being used
- F02D41/3023—Controlling fuel injection according to or using specific or several modes of combustion characterised by the mode(s) being used a mode being the stratified charge spark-ignited mode
- F02D41/3029—Controlling fuel injection according to or using specific or several modes of combustion characterised by the mode(s) being used a mode being the stratified charge spark-ignited mode further comprising a homogeneous charge spark-ignited mode
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/12—Improving ICE efficiencies
Definitions
- the present invention relates to a method for control of a combustion engine, according to the preamble of appended claim 1.
- the invention is particularly intended for use during control of a combustion engine of the direct-injected Otto cycle engine type between two modes of operation which are characterized by different air/fuel mixtures to the engine, preferably a first mode for stratified operation and a second mode for homogeneous operation.
- the invention also relates to an arrangement for such a control, according to the preamble of appended claim 9.
- a lean exhaust gas mixture will flow through the three-way catalyst.
- the three-way catalyst can not be utilized for reducing the NO x compounds in the exhaust gases (due to the fact that it is constructed for an optimal degree of purification for a stoichiometric mixture).
- a conventional three-way catalyst can be combined with a nitric oxide adsorbent (also called NO x adsorbent, or "NO ⁇ trap”), which is a per se known device for absorption of NO x compounds, e.g. in the exhaust gases from a combustion engine.
- NO ⁇ trap nitric oxide adsorbent
- the NO x adsorbent can be utilized as a complement to a conventional three-way catalyst, either as a separate unit upstream of the three-way catalyst or as an integral part of the three-way catalyst, i.e. together with the catalytic material of the three-way catalyst. In the latter case, an integrated component in the form of a NO x adsorbing exhaust catalyst is formed.
- the NO ⁇ adsorbent is constructed in such manner that it takes up (adsorbs) NO ⁇ compounds in the exhaust gases if the engine is operated by a lean air/fuel mixture and gives off (desorbs) the NO x compounds if the engine is operated by a rich air/fuel mixture during a certain time period. Furthermore, the NO x adsorbent has the property of being able only to adsorb NO x compounds up to a certain limit, i.e. it is eventually "filled” and thus reaches a limit for the adsorption. In this situation, the NO x adsorbent must be regenerated, i.e. it must be influenced to desorb and thus to release the accumulated NO x compounds.
- a conventional three-way catalyst in this case is arranged downstream of a NO x adsorbent, or if alternatively a three- way catalyst is formed as an integral part of a NO x adsorbent, the desorbed NO ⁇ compounds can be eliminated by means of the three-way catalyst, provided that the latter has reached its ignition temperature.
- a NO x adsorbent can be regenerated by means of the fact that the exhaust gas mixture which flows through the NO x adsorbent is made comparatively rich during a certain time period, approximately a few seconds. In practice, this is achieved by operating the engine during this time period in the above-mentioned homogeneous mode of operation, wherein the engine thus is operated by a comparatively rich air/fuel mixture. In this manner, the NO x adsorbent is "emptied" so that it subsequently can adsorb NO ⁇ compounds during a certain time period which lasts until a new regeneration becomes necessary.
- a switch between stratified and homogeneous mode can occur by means of an adjustment of the air/fuel mixture which is supplied to the engine and the progress in time for the injection of said mixture.
- This switch is normally initiated as a result of the engine's driver requesting a changed torque from the engine. This is provided by means of a detection of the position of the engine's accelerator pedal.
- the vehicle comprises a computer based control unit which, depending on the required torque, secures that a suitable air/fuel mixture is fed to the engine depending on whether a stratified or a homogeneous operation prevails and depending on, for example, the prevailing torque and engine speed of the engine.
- the engine Apart from a driver-initiated switch from, for example, stratified to homogeneous operation, the engine also must be switched to the homogeneous mode of operation in a compulsory manner (i.e. independent of whether the prevailing driving situation corresponds to homogeneous operation or not) when the control unit has estimated that a regeneration of the NOx adsorbent is necessary. This requirement usually occurs after a certain time period has passed from a previous regeneration or after a certain amount of NO x compounds has been fed into the NO x adsorbent, e.g. when the NO ⁇ adsorbent is full.
- a control unit is in this manner utilized with a suitable strategy for switching the combustion engine between homogeneous and stratified operation depending on the degree of throttle application and the engine speed of the engine, and with regard to whether a NO x regeneration is necessary.
- the object of the present invention is to provide an improved method for control of a combustion engine.
- the object of the invention is to provide an optimized switch between two modes of operation in a DI engine, preferably homogeneous and stratified operation. Said object is accomplished by means of a method, the characterizing features of which will be apparent from appended claim 1. Said object is also accomplished by means of an arrangement, the characterizing features of which will be apparent from appended claim 9.
- the invention relates to a method for control of a combustion engine of the DI engine type, which method comprises generation of an air/fuel mixture to the respective cylinders of the engine, and switch between at least a first mode of operation and a second mode of operation of the engine by means of adjustment of the air/fuel mixture which is supplied to the engine and the progress in time for the injection of said mixture.
- the invention is characterized in that said switch of mode of operation is initiated in connection with operation of the engine with an air/fuel mixture which is adjusted in such manner that correct operation of the engine is allowed in both said modes of operation during said switch.
- the switch between various modes of operation is instead adjusted so that a stable combustion in the engine is maintained during the entire switch between prevailing modes of operation.
- a switch between the various modes of operation is achieved without any noticeable torque changes in the engine, which constitutes an advantage as regards the comfort for the passengers of the vehicle. Also, to some extent, the emissions of the engine can be reduced.
- the invention is based on the fact that the values regarding the lambda figures which correspond to a required air/fuel mixture to the engine are calculated continuously for any of the possible modes of operation and for the requested mode of operation for the engine before as well as after a switch.
- NO x adsorbing exhaust catalyst refers to an integrated component which comprises NO x adsorbing material as well as material which provides the function of a conventional three-way catalyst.
- mode of operation refers to operation of a combustion engine of the DI engine type according to a predetermined progress in time for injection of fuel and ignition of an air/fuel mixture.
- a mode of operation of a DI engine can be mentioned stratified and homogeneous mode of operation.
- the term "fuel control” is utilized in order to define either a nominal fuel control, which corresponds to the fact that air and fuel into the engine are dosed in accordance with predetermined amounts during the prevailing driving condition (e.g. depending on the engine speed of the engine and its required torque), or an air-based fuel control, wherein air into the engine is dosed in accordance with a predetermined amount during the prevailing driving condition (e.g. depending on the engine speed of the engine and its requested torque) and fuel into the engine is dosed in accordance with the prevailing amount of inflowing air.
- a nominal fuel control which corresponds to the fact that air and fuel into the engine are dosed in accordance with predetermined amounts during the prevailing driving condition (e.g. depending on the engine speed of the engine and its required torque)
- an air-based fuel control wherein air into the engine is dosed in accordance with a predetermined amount during the prevailing driving condition (e.g. depending on the engine speed of the engine and its requested torque) and fuel into the engine is dosed in accordance with
- Fig. 1 is a principal diagram of an arrangement in which the present invention can be utilized.
- Fig. 2 is a slightly simplified flow chart which describes the function of the invention.
- Fig. 1 shows a schematic view of an arrangement according to the present invention.
- the invention is arranged in connection with a combustion engine 1 which is constituted by a so-called DI engine, i.e. an engine of the direct-injected Otto cycle engine type, where the injection of fuel to the engine 1 is adapted for at least two modes of operation with different air and fuel supply to the engine 1 and a varying progress in time for injection of fuel and for the ignition of the air/fuel mixture.
- DI engine i.e. an engine of the direct-injected Otto cycle engine type
- the engine 1 preferably can be set in a "homogeneous" mode of operation during certain operating cases at comparatively high torques and engine speeds of the engine 1 , wherein a stoichiometric or a comparatively rich mixture is supplied to the engine 1.
- this mixture - in contrast to what is the case during the stratified mode of operation - is essentially uniformly distributed in the combustion chamber.
- the engine 1 is assumed to be operated either in a stratified or a homogeneous manner.
- the invention is not limited to merely these two modes of operation.
- the air/fuel mixture is comparatively lean, approximately 1 ,2-1 ,3.
- the engine 1 is in a conventional manner supplied with inflowing air via an air inlet 2. Furthermore, the engine 1 is provided with a number of cylinders 3 and a corresponding number of fuel injectors 4.
- the respective injector 4 is connected to a central control unit 5 via an electrical connection 6.
- the control unit 5 is computer based and is adapted to control the fuel supply to each injector 4 with fuel from a fuel tank (not shown) in a known manner so that a constantly adapted air/fuel mixture is fed to the engine 1.
- the engine 1 according to the embodiment is formed in accordance with the "multi-point" injection type, where the correct amount of fuel to the engine 1 can be supplied individually to the respective injector 4 in a known manner.
- the control unit 5 is adapted in a general manner to control the air/fuel mixture to the engine 1 so that it in every given moment is adapted to the prevailing mode of operation.
- the control of the engine 1 takes place in an essentially known manner depending on various parameters which reflect the mode of operation of the engine 1 and the vehicle in question.
- the control of the engine can take place depending on the prevailing degree of throttle application, the engine speed, the amount of injected air to the engine and the oxygen concentration in the exhaust gases.
- the engine 1 is provided with, for example, a position indicator 7 for the vehicle's accelerator pedal (not shown), an engine speed indicator 8 for detection of the engine speed of the engine 1 and an air flow meter 9 for detection of the amount of supplied air to the engine 1 , all of which are connected to the control unit 5 via corresponding electrical connections 10, 11 and 12, respectively.
- the system comprises a gas throttle 13, which preferably is electrically controllable and, for this reason, is provided with a controllable shifting motor 14, by means of which the gas throttle 13 can be set in a certain desired position so that a suitable amount of air is fed into the engine 1 depending on the prevailing mode of operation.
- the shifting motor 14 is connected to the control unit 5 via an additional connection 15.
- the engine 1 is adapted to be able to assume several different modes of operation, each of which is characterized by specific air/fuel mixtures, injections times and ignition times.
- the control unit 5 is adapted to change between the various modes of operation depending on, for example, the driving situation, the load and the engine speed.
- the engine 1 that is shown in the drawing is of a five-cylinder type. However, it shall be noted that the invention can be utilized in engines having various numbers of cylinders and various cylinder configurations.
- the injectors 4 are constituted by the type in which the fuel is injected directly into the respective cylinder 3.
- a NO x adsorbing exhaust catalyst 18 is provided further downstream along the exhaust pipe 17, which exhaust catalyst in turn is constructed of a three-way catalyst that is integrally formed with a NO x adsorbent.
- the exhaust catalyst is of a per se known type and is adapted to adsorb NO x compounds which flow out from the engine 1 via the exhaust pipe 8.
- the exhaust catalyst 18 is constituted by an integrated unit which on the one hand comprises NO x adsorbing material and on the other hand comprises a precious metal which provides the function of a per se conventional three-way catalyst.
- NO x adsorbing exhaust catalyst alternatively (shortened) "exhaust catalyst”
- exhaust catalyst exhaust catalyst
- the invention can comprise a NO x adsorbent which is arranged as a separate component in connection with a three-way catalyst.
- the NO x adsorbent 18 is schematically indicated in the drawing as a single unit.
- the engine 1 is connected to a pre-catalyst 19 which is arranged upstream of the exhaust catalyst 18.
- the pre-catalyst 19 is particularly adapted for rapid heating during cold starts of the engine 1 , i.e. so that its catalytic coating becomes active rapidly. This provides a considerable elimination of HC, CO, and NO x compounds in the exhaust gases, particularly during low idle flows.
- a comparatively short ignition time is provided for the subsequent exhaust catalyst 18, i.e. a comparatively short time that passes until the exhaust catalyst 18 has been heated to a temperature at which it is capable of reducing a predetermined part of the harmful substances in the exhaust gases. This results in a more effective exhaust purification for the engine 1. This improvement is particularly useful during cold starts.
- the exhaust gases from the engine 1 flow through the exhaust pipe 17, through the pre-catalyst 19 and the exhaust catalyst 18 and then further out into the atmosphere.
- the exhaust catalyst 18 functions as a conventional three-way catalyst, i.e. for elimination of hydrocarbons (HC), carbon monoxide (CO) and nitric oxide compounds (NO x ).
- HC hydrocarbons
- CO carbon monoxide
- NO x nitric oxide compounds
- the arrangement according to the invention comprises a sensor 20 for detection of the oxygen concentration in the exhaust gases.
- the sensor 20 is of the linear lambda probe type (but may alternatively be constituted by a binary probe) and is connected to the control unit 5 via an electrical connection 21.
- the sensor 20 is provided in the exhaust pipe 17, upstream of the pre-catalyst 19.
- the sensor 20 is utilized for generation of a signal which corresponds to the oxygen concentration in the exhaust gases. Said signal is fed to the control unit 5 via the connection 21 and is utilized for control of the air/fuel mixture to the engine 1.
- the engine 1 provides a desired torque as quickly as possible, while the emissions from the engine 1 are minimized.
- the engine 1 is adapted to be driven in a stratified operation, with a very lean air/fuel mixture.
- the engine 1 is also adapted to be driven in a homogeneous mode of operation, i.e. with a stoichiometric or essentially stoichiometric mixture.
- the invention is not limited to these two modes of operation, but may also, for example, be operated in a lean, homogeneous or a rich, homogeneous manner etc.
- the choice of mode of operation takes place in accordance with tables which have been fixed in advance and which are stored in a memory unit in the control unit 5.
- the control unit 5 can determine whether the engine 1 shall be positioned in, for example, the stratified or the homogeneous mode of operation.
- a prevailing value of, for example, the prevailing inflowing amount of air into the engine may alternatively be utilized.
- the switch between stratified and homogeneous operation can also be made compulsory as a consequence of a demand for regeneration of the exhaust catalyst 18.
- This can be made in the following manner.
- the engine 1 is operated in a stratified manner, i.e. with a lean air/fuel mixture
- the exhaust gas mixture which flows through the exhaust pipe 17 and reaches the exhaust catalyst 18 is also lean.
- the major part of the NO x compounds which are present in the exhaust gas mixture will be adsorbed by the exhaust catalyst 18.
- the exhaust catalyst 18 After driving with a lean exhaust gas mixture for a certain amount of time, normally approximately 1-2 minutes, the exhaust catalyst 18 will be "full", which means that the exhaust catalyst 18 is unable to absorb NO x compounds from the exhaust gas mixture to the same extent as previously.
- the exhaust catalyst 18 must be regenerated.
- the demand for regeneration can be determined by means of the control unit 5, which in this case sets the engine 1 in the homogeneous mode of operation. This makes it possible to make the exhaust gas mixture through the exhaust catalyst 18 comparatively rich during a certain time period, e.g. during a few seconds. In this manner, NO x compounds which previously have been adsorbed in the exhaust catalyst 18 are desorbed, so that this once again is allowed to adsorb NO x compounds during a certain time period which lasts until it becomes necessary with a new regeneration. When the NO x compounds have been desorbed from the exhaust catalyst 18, they will also be reduced by means of the catalytic coating which constitutes an integrated part of the exhaust catalyst 18.
- the adsorbed NO x compounds can be reduced directly without an intervening desorption if the exhaust catalyst is of the type which is constructed as an integrated three-way catalyst and a NO x adsorbent.
- the times at which it is suitable to make the regeneration can be calculated by means of the control unit 5, and is determined depending on, among other things, the exhaust catalyst 18 and its storage capacity for NO x compounds and its degree of transformation. Said storage capacity of the exhaust catalyst 18 is also affected by a possible ageing and deactivation depending on sulphur compounds. When an excessive amount of sulphur has accumulated in the exhaust catalyst 18, sulphur regeneration must be carried out. This can be made according to prior art and will not be described in detail here.
- the control unit 5 is adapted for suitable fuel control of the engine 1 , i.e. for adjustment of an air/fuel mixture which is adapted in a suitable manner in accordance with the prevailing mode of operation at a given driving situation. More precisely, the control unit is adapted either for a so-called nominal fuel control, wherein set values regarding the amount of air and fuel to the engine are determined in accordance with predetermined amounts at a given driving situation (e.g. depending on the engine speed of the engine and its required torque), or a so-called air-based fuel control, wherein air into the engine is dosed in accordance with a predetermined amount at the prevailing driving situation (e.g. depending on the engine speed of the engine and its required torque) and fuel to the engine is dosed in accordance with the prevailing amount of air.
- a predetermined amount at the prevailing driving situation e.g. depending on the engine speed of the engine and its required torque
- the invention is based on the fact that the fuel amount to the engine can be changed momentarily, whereas the amount of air to the engine has a great inertia during possible changes.
- the torque out from the engine only depends on the amount of injected fuel. Small changes of the amount of air do not affect the torque since there is an excess of air. For this reason, a nominal fuel amount is then utilized.
- a nominal fuel amount is then utilized.
- exact proportions between fuel and air are required in order to minimize the emissions. In order to accomplish this, a certain amount of air is directed out for a given set value. However, it takes a certain time before this amount of air arrives.
- an air-based fuel control is utilized, wherein it is secured that the amount of air in a subsequent piston stroke is estimated on the basis of the pressure in the induction pipe and the measured amount of air before the gas throttle 13.
- the control unit 5 it is secured that the exact amount of fuel (which corresponds to said amount of air) is injected into the respective cylinder 3.
- Fig. 2 shows a simplified flow chart which describes the function of the invention in connection with a switch from the stratified to the homogeneous mode of operation.
- the engine 1 in the initial position, it is assumed that the engine 1 is operated in the stratified mode of operation, which corresponds to a comparatively low torque and a comparatively low engine speed of the engine 1. According to what has been described above, the engine 1 generates a lean exhaust gas mixture in this condition.
- both an optimized occasion for mode switch i.e. in the prevailing case a switch of the progress of injection and the fuel supply from stratified to homogeneous, and an optimized occasion for switch between nominal and air-based fuel control is initiated.
- the calculated value of the required braked torque is compensated in the control unit 5 with regard to the prevailing estimated pump and friction losses in the engine 1 Said losses can be estimated on the basis of the temperature of the cooling water of the engine 1 , which in turn can be determined by means of a (not shown) temperature indicator for the cooling water
- a compensated torque (or "indicated" torque) is provided on the basis of the braked torque
- the control unit 5 determines a nominal amount of fuel M s and M h , respectively, for the stratified and the homogeneous mode of operation, respectively (square 24) This is determined by means of tables which are stored in advance in the control unit 5 and which indicate a connection between the compensated torque and said fuel amounts M s , M h for each mode of operation
- the next step is the determination of a set value ⁇ se t regarding the air/fuel mixture which shall prevail in the requested mode of operation, i e in the prevailing case in the homogeneous operation (square 26)
- the control unit 5 is provided with tables which indicate a suitable set value ⁇ se t for each driving situation and mode of operation
- this set value ⁇ set in a homogeneous mode of operation is approximately 1
- the set value is approximately 1 , 5-3, depending on the driving situation
- the above-mentioned gas throttle 13 (cf. Fig. 1 ) is also activated for adjustment of a homogeneous amount of air (square 27). Due to the fact that a mode switch now has been requested, the gas throttle 13 will start to readjust.
- the invention is based on the fact that it is impossible to change the amount of air in to the engine momentarily, but that it takes a certain time to change the amount of air to the homogeneous amount of air in order to reach the determined set value ⁇ set . For this reason, the mode switch can not be initiated until the amount of air has been changed to such extent that a correct operation of the engine is allowed in both the prevailing modes of operation during a certain short time period.
- a mode switch can not occur until a certain limit condition has been fulfilled.
- This limit condition can be expressed either as a maximum lambda value that is allowed to prevail in the homogeneous mode of operation or as a minimum lambda value that is allowed to prevail in the stratified mode of operation.
- the invention is not limited to this variant, but other strategies for selection of limit conditions are possible as long as a satisfactory operation of the engine through the whole mode switch can be accomplished.
- the prevailing lambda value also turns inwards to the set value ⁇ set , which is due to the fact that the fuel amount is predetermined according to the prevailing, nominal fuel control.
- control unit 5 is adapted to detect whether the prevailing lambda value ⁇ for the homogeneous mode of operation has been changed to such extent that it is lower than a predetermined limit value, i.e. if ⁇ h ⁇ , wherein this limit value ⁇ i preferably is approximately 1 , 2. If this is the case (square 28), this will result in that a switch to a homogeneous mode of operation (square 29) occurs. Thus, this implies that the progress in time for supply of fuel and air to the engine 1 and the progress in time for ignition of air/fuel mixture changes from stratified to homogeneous type.
- the above-mentioned limit value ⁇ i is predetermined and preferably approximately 1 ,2. More precisely, this limit value is selected as the highest value where a stable combustion in the engine 1 is provided during the mode switch. The fact is, that if a switch from stratified to homogeneous mode of operation occurs at a too low limit value, an undesired carbon deposit from the engine 1 will occur. If, according to what has been described above, the switch instead occurs at too high limit value (i.e. a too lean homogeneous mode of operation), an unstable combustion occurs, which can result in torque loss or misfire of the engine.
- the prevailing lambda value will have decreased to such extent that it is lower than a second, predetermined limit value, i.e. ⁇ h ⁇ 2 (square 30).
- a second, predetermined limit value i.e. ⁇ h ⁇ 2 (square 30).
- the type of fuel control changes (square 31 ) and follows the per se known air-based type of injection at which the required amount of fuel for the respective moment of operation of the engine 1 is calculated depending on the prevailing air flow to the engine 1.
- the last-mentioned limit value ⁇ 2 is selected sufficiently low so that it do not result in a too high addition of torque, which is a drawback as regards the comfort, since it is perceived as a jerk for the passengers of the vehicle.
- the mode switch occurs at a too high lambda value ⁇ h, an unstable combustion will occur, which can result in torque loss or misfire.
- the switch of fuel control occurs at a too high lambda value ⁇ h, a torque change in the form of an undesired addition of torque will occur, which is a drawback as regards the comfort, since it is perceived as a jerk for the passengers of the vehicle.
- the switches occur at limit values which are adjusted in order to avoid said drawbacks.
- an essential advantage is provided in the form of a stable combustion in the engine during the mode switch. Also, an improved comfort is provided for the passengers in the vehicle in question. More precisely, by means of the invention, switches between the stratified and the homogeneous mode of operation (and any additional modes of operation which possibly will occur) are provided which are smooth and without jerks.
- a switch of fuel control i.e. from air-based to nominal fuel control
- a switch of fuel control occurs immediately after a switch to stratified mode of operation has been requested.
- the lambda value then exceeds a predetermined limit value which corresponds to a stable combustion and a switch which is without jerks, the engine will be switched to the stratified mode of operation.
- the invention is not limited to the embodiments which are described above and shown in the drawings, but may be varied within the scope of the appended claims.
- the invention can be utilized without a pre- catalyst 19.
- the invention can be utilized in those cases where a NO ⁇ adsorbent and a conventional three-way catalyst are arranged as two separate components, instead of the above-mentioned embodiment where said two components have been integrated into one single component in the form of a NO x adsorbing exhaust catalyst.
- the invention also can be utilized in connection with engines which do not comprise a NO x adsorbent.
- the fuel control changes abruptly when the lambda values are sufficiently close to each other.
- the invention can also be utilized in connections which comprise a gradual transition from, for example, a nominal to an air-based fuel control, e.g. based on the prevailing lambda value.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE9902567 | 1999-07-05 | ||
SE9902567A SE521717C2 (en) | 1999-07-05 | 1999-07-05 | Procedure for controlling combustion engine, and arrangements for such process |
PCT/SE2000/001224 WO2001002708A1 (en) | 1999-07-05 | 2000-06-13 | Method for controlling a combustion engine, and arrangement for such a method |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1192342A1 true EP1192342A1 (en) | 2002-04-03 |
EP1192342B1 EP1192342B1 (en) | 2005-10-12 |
Family
ID=20416381
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP00944512A Expired - Lifetime EP1192342B1 (en) | 1999-07-05 | 2000-06-13 | Method for controlling a combustion engine, and arrangement for such a method |
Country Status (5)
Country | Link |
---|---|
US (1) | US6609364B2 (en) |
EP (1) | EP1192342B1 (en) |
DE (1) | DE60030856T2 (en) |
SE (1) | SE521717C2 (en) |
WO (1) | WO2001002708A1 (en) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2005075803A1 (en) * | 2004-02-09 | 2005-08-18 | Hitachi, Ltd. | Engine controller |
US7159387B2 (en) | 2004-03-05 | 2007-01-09 | Ford Global Technologies, Llc | Emission control device |
US7367180B2 (en) * | 2004-03-05 | 2008-05-06 | Ford Global Technologies Llc | System and method for controlling valve timing of an engine with cylinder deactivation |
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1999
- 1999-07-05 SE SE9902567A patent/SE521717C2/en not_active IP Right Cessation
-
2000
- 2000-06-13 WO PCT/SE2000/001224 patent/WO2001002708A1/en active IP Right Grant
- 2000-06-13 EP EP00944512A patent/EP1192342B1/en not_active Expired - Lifetime
- 2000-06-13 DE DE60030856T patent/DE60030856T2/en not_active Expired - Lifetime
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2001
- 2001-12-20 US US09/683,390 patent/US6609364B2/en not_active Expired - Fee Related
Non-Patent Citations (1)
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EP1192342B1 (en) | 2005-10-12 |
SE9902567L (en) | 2001-01-18 |
US6609364B2 (en) | 2003-08-26 |
SE9902567D0 (en) | 1999-07-05 |
DE60030856D1 (en) | 2006-11-02 |
DE60030856T2 (en) | 2007-08-16 |
SE521717C2 (en) | 2003-12-02 |
US20020053335A1 (en) | 2002-05-09 |
WO2001002708A1 (en) | 2001-01-11 |
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